I'm trying to get a list of computers that does NOT have a specific hotfix installed. "In software installed" I can create a filter to only include hotfixes and exclude a specific hotfix. But I end up with a long list of the different other hotfixes which is not what I want. So basically how do I create a filter to show me all units that does not have a specific hotfix installed?

Then put an advanced filter. Choose SQL mode To display all computers with Microsoft software, without the updates, hotfixes, etc., put in this:([Product_Name] Not Like N'%hotfix%') and ([Product_Name] Not Like N'%security update%') and ([Product_Name] Not Like N'%update%') and ([Product_Name] Not Like N'%service pack%') and ([Product_Name] Not Like N'%add-in%') and ([Product_Name] Not Like N'%language pack%') and (([Product_Name] Like N'microsoft%') or ([Manufacturer] Like N'microsoft%'))

------- edit:In your case, getting all computers without hotfix, try in Discovered Installations:([Product_Name] Not Like N'%hotfix%') and ([Product_Name] Like N'microsoft%')

and group on Computer Nameto limit the amount of results filter also on the Product_Name, like in this case microsoft.